Package org.apache.catalina

Interface Loader

All Known Implementing Classes:

WebappLoader

public interface Loader

A Loader represents a Java ClassLoader implementation that can be used by a Container to load class files (within a repository associated with the Loader) that are designed to be reloaded upon request, as well as a mechanism to detect whether changes have occurred in the underlying repository.

In order for a Loader implementation to successfully operate with a Context implementation that implements reloading, it must obey the following constraints:

• Must implement Lifecycle so that the Context can indicate that a new class loader is required.
• The start() method must unconditionally create a new ClassLoader implementation.
• The stop() method must throw away its reference to the ClassLoader previously utilized, so that the class loader, all classes loaded by it, and all objects of those classes, can be garbage collected.
• Must allow a call to stop() to be followed by a call to start() on the same Loader instance.
• Based on a policy chosen by the implementation, must call the Context.reload() method on the owning Context when a change to one or more of the class files loaded by this class loader is detected.

Author:

Craig R. McClanahan

Method Summary

Modifier and Type	Method	Description
void	addPropertyChangeListener(PropertyChangeListener listener)	Add a property change listener to this component.
void	backgroundProcess()	Execute a periodic task, such as reloading, etc.
ClassLoader	getClassLoader()
Context	getContext()
boolean	getDelegate()
boolean	modified()	Has the internal repository associated with this Loader been modified, such that the loaded classes should be reloaded?
void	removePropertyChangeListener(PropertyChangeListener listener)	Remove a property change listener from this component.
void	setContext(Context context)	Set the Context with which this Loader has been associated.
void	setDelegate(boolean delegate)	Set the "follow standard delegation model" flag used to configure our ClassLoader.

Method Details

backgroundProcess

void backgroundProcess()

Execute a periodic task, such as reloading, etc. This method will be invoked inside the classloading context of this container. Unexpected throwables will be caught and logged.

getClassLoader

ClassLoader getClassLoader()

Returns:

the Java class loader to be used by this Container.

getContext

Context getContext()

Returns:

the Context with which this Loader has been associated.

setContext

void setContext(Context context)

Set the Context with which this Loader has been associated.

Parameters:

context - The associated Context

getDelegate

boolean getDelegate()

Returns:

the "follow standard delegation model" flag used to configure our ClassLoader.

setDelegate

void setDelegate(boolean delegate)

Set the "follow standard delegation model" flag used to configure our ClassLoader.

Parameters:

delegate - The new flag

addPropertyChangeListener

void addPropertyChangeListener(PropertyChangeListener listener)

Add a property change listener to this component.

Parameters:

listener - The listener to add

modified

boolean modified()

Has the internal repository associated with this Loader been modified, such that the loaded classes should be reloaded?

Returns:

true when the repository has been modified, false otherwise

removePropertyChangeListener

void removePropertyChangeListener(PropertyChangeListener listener)

Remove a property change listener from this component.

Parameters:

listener - The listener to remove